1. Field of the Invention
The present invention generally relates to a memory device. More particularly, the present invention relates to a dynamic memory device having a large capacity.
2. Description of the Prior Art
Conventionally, a dynamic memory device is well known in that it can be manufactured at low manufacturing cost levels per bit, it is formed so as to be small in size with a large capacity, and it can be operated at a high rate of speed in comparison with static memory devices. Therefore, the dynamic memory device has been commonly and broadly used as a data processor which requires a large memory capacity and high speed processing.
However, an operation for refreshing the information stored in the dynamic memory device, that is, a "refreshing operation", should be executed within an interval of time of 2 ms, so that such a dynamic memory device cannot be used for storing or reading the information during such a refreshing operation. Thus, such a conventional dynamic memory device causes a problem in that the storing and reading speed of the data processor including such a dynamic memory device is limited.